Thread lock lift plug



June 1954 w. L. MEDDERS THREAD LOCK LIFT PLUG 3 Sheets-Sheet 1 FiledJune 4, 1949 IN V EN TOR. Weldon bMeddem' 47/ 1" ?&

ATTORNEY J1me 1954 w, L. MEDDERS THREAD LOCK LIFT PLUG 3 Sheets-Sheet 2Filed June 4, 1949 IN V EN TOR. WeldOn L Meddem yam ATTOQNE Y June 22,1954 w. L. MEDDERS 2,681,821

THREAD LOCK LIFT PLUG Filed June 4, 1949 3 Sheets-Sheet I5 We/oon L.Meoaem INVENTOR.

A TTOR/Ve) Patented June 22, 1954 THREAD LOCK LIFT PLUG Weldon L.Medders, Houston, Tex., assignor to Houston Oil Field Material Company,Inc., Houston, Tex., a corporation of Delaware Application June 4, 1949,Serial No. 97,185

9 Claims.

This invention relates to a locking type of lift plug for use inmanipulating pipe, and more particularly relates to a thread lock liftplug.

The present invention is capable of use under various circumstances butis particularly useful in connection with well drilling operations wherethe drill pipe is lowered and removed from the well bore. In the use ofwhat is known as flush joint drill pipe, where the outer surface of thethreaded pipe connection is flush so as to provide less friction to thecirculation of drilling mud in the well bore and so as to permit thepipe to be moved through valves and blow-out preventers because of itsuniform outer diameter, considerable difficulty is encountered insupporting the pipe with the hoisting equipment and the practice hasbeen developed of inserting lift plugs in the upstanding end of the pipeso as to provide an outstanding shoulder to permit supporting of thepipe in the elevator or slips.

It is customary practice to provide one such lift plug for every threejoints of drill pipe in lowering the pipe into or removing it from thewell bore. These lift plugs must be screwed tightly into the pipe inorder that the greatest care is exercised to prevent unscrewing of theplug and therefor the lift plug is usually made up or wedged tightlyinto the pipe. With the plugs now in use the general practice is toutilize a heavy sledge hammer in making up the lift plug into thethreads of the pipe and the reverse operation is performed in knockingthe plug loose. There have been instances, however, where such plugshave become loosened and permitted the pipe to drop into the hole.

It is a feature of the invention to provide such a lift plug which maybe made up or released by hand in a minimum of time and labor.

It is an object of the invention to provide a lift plug of minimum partsand which is rugged and which may be easily and economicallymanufactured for all sizes of pipe and which will automatically lock inposition but which is capable of being readily released for removal.

It is an object 'of the invention to provide a lift plug which willwedge in the threads of the pipe by thread means or securing means inthe plug of a pitch different from the threads in the pipe, but willreadily. release by the particular releasing operation. i

It is a further feature of the invention to provide a lift plugpossessingthe above advantages which may be connected to the pipe so asto provide a shoulder below which the hoisting mechaw nism may beconnected so as to lower or raise the pipe.

Other and further objects will be apparent from the followingdescription taken in connection with the accompanying drawings wherelike references designate like parts throughout the several views andWhere Figure 1 is a plan view, with parts broken away, illustrating thelift plug and Wrench therefor in position to either thread or unthreadthe plug from the pipe,

Figure 2 is taken along the line 2-2 of Figure 1 and is a sideelevation, partly in section, illustrating the lift plug threaded into asection of pip Figure 3 is a side elevation illustrating a preferredform of my lift plug,

Figure 4 is a fragmentary detail of the special wrench taken along theline 4-4 of Figure 1,

Figure 5 is a plan view of a modification of my lift plug and wrench,and is generally similar to Figure 1,

Figure 6 is taken along the line 6-6 of Figure 5 and illustrates a sideelevation, partly in section, of the modified form shown in Figure 5,

Figure '7 is a side elevation of the modified form of lift plug, and

Figure 8 is a diagrammatic view of typical hoisting equipment securedabout a pipe to be lifted and engaging the lower shoulder of the liftplug of the invention.

Referring to the drawings, and particularly to Fig. 2, the lift pluggenerally designated by the numeral I0 is illustrated as connected tothe upper section of a pipe l2, which pipe is of the flush joint type ofpipe where the outer periphery I4 is of uniform diameter. The upper endof the pipe is formed with the threaded box I6 which receives'acomplementary threaded pin end (not shown) of the next section of pipewhen the string of pipe is connected together.

The plug 10 has the enlarged collar portion or body l8 provided with thelower shoulder 20 to make up against the end 22 of the pipe l4 when theplug Il is threaded in the threaded box l2 of the pipe [4.

The plug H] has a unitary pin II which is formed of a first pin member25 which extends from the body or collar portion It and a second pinmember 36 which is positioned adjacent the first pin member to provideacontinuation of the first pin member 26 and form the unitary pin ll. Thefirstand second pin members 26 and 36, respectively, arethreaded at 24-and 38, respec- 1 tively, to. form, acontinuous thread which may 3 bemade up or threaded into the threaded box I6 of the pipe l2.

In order that the first and second pin members 26 and 36, respectively,may movably be secured together and by separation of the first andsecond pin members 26 and 36, respectively, of the unitary pin 1 Iprovide a wedging action with the threaded box It, the plug I isprovided with a longitudinal cylindrical bore 28 therethrough and has arelatively fine threaded portion 30 at its upper end with respect to thethreads I6 and 24. A cylindrical shaft or shank it having acomplementary threaded portion 34 to the threads 30 proximate its upperend isthreaded into the bore 28. The second pin member 36 is integralwith the lower portion of the shank 32 and is, in efiect, an enlargedcircumferential flange having the externally threaded portion 28thereon, as previously 7 described. Thus the threaded pin l l is made upof two relatively movable portions held together by threads of a pitchdifierent from those threads on the pin l I of the lift plug. The lowerinner end of the 'bore 28 of the first pin member 26 is chamfered at 4B,and the upper extending end 42 of the shank 32 has the flattened sidesor wrench fiats 44, both for a purpose to be described later.

In order that the lift plug may be threaded into or unthreaded from thepipe, the upper portion of the collar 18 may be straddle milled toprovide the wrench flats or longitudinal shoulders 46 which may besubstantially in alignment with the wrench flats 44 of theextension 42of the shaft 32. A wrench 58 having the jaws 50 adapted to engage thewrench flats 46 of the collar 18 has a plate member .52 secured acrossthe jaws by means of the cap screws 54. The wrench plate member 52 has aslot 56 of generally elongated configuration, the slot being inalignment with the jaws and adapted to fit over the upper extension 42of the shank32 and engage the wrench fiats 44 of the former. Asillustrated a ball crank handle may be disposed at the end of the wrenchhandle 58.

It is manifest that when the wrench is in the position illustrated inFigs. .1 and 2, the first and second pin members 26 and 36,respectively, forming the unitary pin II, will be held as a unit wherebythe device may be turned as a unit.

When the plug I0 is threaded into the pipe l4,

as illustrated in Fig. 2, and the wrench removed, the hoistingequipment; such as illustrated in Figure 8, as later described, mayengage the shoulder 29 of the plug I0 in order that the pipe i2 may beraised or lowered. The plug is automatically locked into positioninasmuch as the plug and shank must rotate as a unit in order to preventWedging of the threaded areas due to the difference in pitch of thethreaded areas effectuating a wedging thereof and thereby effec tivelypreventing the lift plug from uncoupling. It is manifest that thethreaded area 38 will be subject to more friction than the interface ofthe lower chamfered end of the pin' extension and the upper face of theradial extension of the shank, thus the elements of the plug will notturn as a unit due to friction; however, "in practice, in cutting thethreads 24 and 34' the shank and plug may be hand made up and a shim maybe placed in a portion of such interface in order to provide a readyrelease between these faces. In practice it has been found that a .063inch semi-hard brass shim is effective for fthe purpose. The imperfectthread may then be turned down. If desired that portion of the shaft 32immediately above the lower radial flange may be slightly enlarged (notshown) to provide a close fit to prevent dirt or debris from enteringthe bore 28. Thus an effective and automatic lock of the lift plug issecured. In

order to unthread the plug, the wrench may be inserted as illustrated inFig. 2 and the shank and plug will rotate as a unit thereby easily andreadily unthreading the plug.

It is believed that the manner of operation and use of this plug isapparent from the above description. By way of summary, however, the

plug is assembled as illustrated in Figs. 2 and 3 and maybe threaded "bythe wrench by hand into the top portion of a string of pipe to bemanipulated. The special wrench threads the plug into the pipe as aunit. The wrenchis then removed and the pipe may be readily lowered orraised by means of hoisting equipment connecting to the pipe just belowthe enlarged collar portion of the plug. As best seen in Figure 8, aconventional elevator 10 is secured to the traveling block 12 which israised and lowered by means of the cable 14 from the top of the derrick'by rig equipment, both not shown. A conventional mud connection 16 isillustrated for circulation of drill fiuid, but no further descriptionof such hoisting equipment is deemed necessary as any conventionalhoisting equipment or arrangement may be used, the hoisting equipment assuch forming no part of the present invention. The plug will beautomatically locked inposition inasmuch as the difference in pitch ofthe threaded areas securing the plug together will cause a wedging inthe threaded areas thereby effectively preventing untimely release of.the plug. After use and it is desired to remove the plug, the wrench maybe positioned as illustrated in Figs. '1 and 2 and the plug unthreadedfrom the pipe by hand.

It will be understood that any type of squared portion or multisidedconfiguration of the plug and shaft extension may be utilized inconnection with a complementary wrench in order to provide turningmovement to the component parts of the plug as a unit.

A modified form of the plug and wrench is shown in Figs. 5 to 7. In thisembodiment the wrench flats '46 are omitted from the collar l3, and theplug has a radial bore 60 to receive the complementary pin 62 secured tothe lug 64 depending from the wrench 5'8. Here the jaws of the wrenchare adapted to engage the wrench fiats 44 of the extension 42 of theshank 32. .Thus the wrench will thread or unthread the plug ID as a unitinto or out of the box portion of a pipe. The threads 30 inthe upperportion of the bore 28 and the complementary threads 34 on the shank 32are relatively faster or coarser than the threads 16, 24 and 38 therebyproviding the wedging action. The remainder of the plug and wrench areidentical with the preferred form and the manner of operation is thesame.

Although I have illustrated relatively fast and coarse'threads to securethe shaft 32 to the lift plug as being preferable, it is manifest thatthe shaft may be secured to the plug in other ways; for example, theshaft may have a spiral groove thereon of a number of turns per unitdifferent from the threads on the pin member/and the plug may beradially counter-bored and a pin inserted thereinto project into thebore to provide a complementary key to the groove in the shaft. While itmay be more diflicult to manufacture, a ball might be utilized in placeof the key, It is important that the means to make up the componentparts be of a pitch different from the threads on the pin member of theplug.

While the invention has been described in detail as applied to a flushjoint pipe, it seems obvious that it may be utilized under various otherconditions.

Broadly my invention contemplates a lock lift plug including relativelymovable component parts secured together by thread means of a pitchdifferent from threads on the pin member whereby the lift plug isautomatically locked in position, and may only be released by turningthe plug as a unit.

I claim:

1. A locking lift plug comprising, a body, an externally threaded firstpin member extending from such body, an externally threaded second pinmember movably secured to said plug, said first and second pin membersforming a unitary externally threaded pin, and securing means of a pitchdifferent from threads on said unitary pin securing such second pinmember to such plug.

2. A locking lift plug for pipe comprising, a body, a first threaded pinmember on said body, a bore through said body and said first threadedpin member, a shaft positioned in said bore, a second threaded pinmember on said shaft, said first and second threaded pin membersdisposed in abutting relationship thereby providing a unitary threadedpin adapted to engage threads in said pipe, and thread means in saidbore and on said shaft of a pitch different from threads on said firstand second threaded pin members threadedly securing said shaft in saidbore.

3. A locking lift plug for pipe comprising, a body, a first threaded pinmember on said body, an axial here through said body and said firstthreaded pin member, a shaft positioned in said axial bore, a secondthreaded pin member on said shaft, said first and second threaded pinmembers disposed in abutting relationship thereby providing a unitarythreaded pin adapted to engage threads in said pipe, and thread means insaid axial bore and on said shaft of a pitch different from threads onsaid first and second pin members threadedly securing said shaft in saidaxial bore.

4. A locking lift plug comprising, a body, an externally threaded firstpin member extending from said body, an externally threaded second pinmember movably secured to said plug, said first and second pin membersforming a unitary externally threaded pin, securing means of a pitchdifferent from threads on said unitary pin securing such secondpinmember to such plug, and means on said body and associated with saidsecond pin member to turn the plug as a unit.

5. A lift plug comprising, a body, an externally threaded first pinmember extending from said body, an externally threaded second pinmember movably secured to said plug, said first and second pin membersforming a unitary externally threaded pin, securing means of a pitchdifferent from threads on said unitary pin securing such second pinmember to such plug, and means on said body and associated with suchsecond pin member to turn the plug as a unit into or out of pipe to bemanipulated, such last mentioned means including a handle havingportions thereon to engage said body and said means associated with suchsecond pin member so that turning of the handle screws or unscrews theplug into or out of said pipe.

6. A locking lift plug for pipe comprising, a body, an externallythreaded first pin member extending from such body, an externallythreaded second pin member movably secured to said plug, said first andsecond pin members providing a continuous externally threaded pin,securing means of a pitch different from threads on said continuous pinsecuring such second pin member to such plug, and means on such body bywhich hoisting mechanism may be secured so as to lower or raise the pipewhen the plug is threaded to the pip 7. A locking lift plug for pipecomprising, a body, an externally threaded first pin member extendingfrom such body, an externally threaded second pin member movably securedto said plug, said first and second pin members forming a continuousexternally threaded pin, and means movably securing such second pinmember to said plug whereby relative movement of said pin memberseffects a separation of such pin members thereby wedging such continuouspin to such pipe when the plug is threaded thereto.

8. A locking lift plug for pipe comprising, a cylindrical body, anannular shoulder at the lower end of the body, a reduced-diameterexternally-threaded first pin member extending from said body below theshoulder, an externallythreaded pin member movably secured to such plug,such first and second pin members forming a unitary externally-threadedpin, means movably securing such second pin member to said plug wherebyrelative movement of said pin members effects a separation of such pinmembers thereby wedging such unitary pin to such pipe when the plug isthreaded thereto, hoisting mechanism secured about the pipe when theplug is threaded thereto engaging the annular shoulder so as to lower orraise the pipe.

9. A locking lift plug for pipe comprising, a cylindrical body, anannular shoulder at the lower end of the body, a reduced-diameterexternally-threaded first pin member extending from said body below theshoulder, an axial bore through the body and the first pin member, ashaft positioned in the axial bore, a second threaded pin member on theshaft, said first and second pin members disposed in abuttingrelationship and providing a unitary threaded pin adapted to engagethreads in said pipe, thread means in the axial bore and on the shaftdifferent from threads on the first and second pin members threadedlysecuring the shaft in the axial bore, and means on the body and on theshaft to thread the plug as a unit into or out of the pipe to bemanipulated, such last-mentioned means including a handle having meansthereon to engage the body and the means on the shaft so that turning ofthe handles screws or unscrews the plug into or out of the pipe,hoisting mechanism secured to the pipe below the plug engaging theshoulder so as to lower or raise the pipe when the plug is threaded tothe pipe.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,518,716 Waugh Dec, 9, 1924 1,532,150 Olson Apr. 7, 19252,534,662 Froom Dec. 19, 1950 2,562,327 Moore July 31, 1951

